Redox‐Controlled Exchange Bias in a Supramolecular Chain of Fe4 Single‐Molecule Magnets |
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| Authors: | Andrea Nava Dr Luca Rigamonti Prof Ennio Zangrando Prof Roberta Sessoli Dr Wolfgang Wernsdorfer Prof Andrea Cornia |
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| Institution: | 1. Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia & INSTM RU of Modena and Reggio Emilia via G. Campi 183, 41125 Modena (Italy) http://www.corniagroup.unimore.it;2. Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, 41125 Modena (Italy);3. Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste, 34127 Trieste (Italy);4. Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica “Ugo Schiff”, Università di Firenze & INSTM RU of Florence, 50019 Sesto Fiorentino (Italy);5. Institut Néel, CNRS, 38042 Grenoble Cedex 9 (France) |
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| Abstract: | Tetrairon(III) single‐molecule magnets Fe4(pPy)2(dpm)6] ( 1 ) (H3pPy=2‐(hydroxymethyl)‐2‐(pyridin‐4‐yl)propane‐1,3‐diol, Hdpm=dipivaloylmethane) have been deliberately organized into supramolecular chains by reaction with RuIIRuII or RuIIRuIII paddlewheel complexes. The products Fe4(pPy)2(dpm)6]Ru2(OAc)4](BF4)x with x=0 ( 2 a ) or x=1 ( 2 b ) differ in the electron count on the paramagnetic diruthenium bridges and display hysteresis loops of substantially different shape. Owing to their large easy‐plane anisotropy, the s=1 diruthenium(II,II) units in 2 a act as effective seff=0 spins and lead to negligible intrachain communication. By contrast, the mixed‐valent bridges (s=3/2, seff=1/2) in 2 b introduce a significant exchange bias, with concomitant enhancement of the remnant magnetization. Our results suggest the possibility to use electron transfer to tune intermolecular communication in redox‐responsive arrays of SMMs. |
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| Keywords: | chain structures iron magnetic properties ruthenium single‐molecule magnets |
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